In Uranium 235 and Uranium 238?

U-235 is the main fissile isotope of uranium. ... The nucleus of the U-235 atom contains 92 protons and 143 neutrons, giving an atomic mass of 235 units. The U-238 nucleus also has 92 protons but has 146 neutrons – three more than U-235 – and therefore has a mass of 238 units.

What do uranium 235 and uranium 238 have in common?

The number gives number of nucleons in a nucleus. uranium-235 has 235 nucleons and uranium-238 has 238 nucleons. The number of protons (which also give a charge to a nucleus) are same in the two, which is 92. The two have different number of neutrons.

Why is U-235 better than U-238?

U- 235 is a fissile isotope, meaning that it can split into smaller molecules when a lower-energy neutron is fired at it. ... U- 238 has an even mass, and odd nuclei are more fissile because the extra neutron adds energy - more than what is required to fission the resulting nucleus.